Mobility management in wireless networks

ABSTRACT

A method for wireless communications includes operating a first network element in a wireless communication network to provide connectivity between a first core network and a user device, wherein the wireless communication network includes a second network element that is configured to provide a secondary connectivity between the first core network and the user device, and communicating, by the first network element, in a handover to a third network element configured to provide connectivity with a second core network, configuration information of the second network element to the third network element.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent document is a continuation of and claims benefit of priorityto U.S. patent application Ser. No. 16/828,922, filed on Mar. 24, 2020,which is continuation of International Patent Application No.PCT/CN2017/104074, filed on Sep. 28, 2017. The entire content of thebefore-mentioned patent applications is incorporated by reference aspart of the disclosure of this application.

TECHNICAL FIELD

This document relates to systems, devices and techniques for wirelesscommunications.

BACKGROUND

Efforts are currently underway to define next generation wirelesscommunication networks that provide greater deployment flexibility,support for a multitude of devices and services and differenttechnologies for efficient bandwidth utilization. For better bandwidthutilizations, various techniques, including new ways to provide higherquality of service, are being discussed.

SUMMARY

This document describes technologies, among other things, for providingmaster and secondary base station support to user devices duringmovement from one cell to another.

In one exemplary aspect, a method for wireless communications isdisclosed. The method includes operating a first network element in awireless communication network to provide connectivity between a firstcore network and a user device, wherein the wireless communicationnetwork includes a second network element that is configured to providea secondary connectivity between the first core network and the userdevice; and communicating, by the first network element, in a handoverto a third network element configured to provide connectivity with asecond core network, configuration information of the second networkelement to the third network element.

In some embodiments, the first core network and the second core networkare the same core network. In some embodiments, the first core networkand the second core network are different core networks.

In some embodiments, the first network element and the third networkelement operate using a first radio access technology (RAT). The firstRAT may be a fourth generation (4G) RAT technology. The first RAT mayalso be a fifth generation (5G) RAT technology.

In some embodiments, the second network element and the fourth networkelement operating using a second RAT. In some implementations, the firstRAT and the second RAT correspond to different protocol standards. Insome implementations, the first RAT and the second RAT correspond to asame protocol standard.

In some embodiments, the configuration information of the second networkelement is communicated using a data structure from one of thefollowing: a container, a container and multiple explicit informationelements, multiple containers, or multiple containers and multipleexplicit information elements.

In another exemplary aspect, a method for wireless communications isdisclosed. The method includes operating a first network element toprovide connectivity to a first core network; receiving, when a userdevice is handed over from a second network element, information fromthe second network element providing connectivity to a second corenetwork, wherein the information identifies properties of a thirdnetwork element providing a secondary connectivity to the second corenetwork; and selectively deciding, based on the information, a secondaryconnectivity network element between the third network element and afourth network element for the first network element, wherein the fourthnetwork element is configured to provide connectivity to the first corenetwork.

In some embodiments, the method also includes, for a newly selectedfourth network element, transmitting the information of the thirdnetwork element to the fourth network element. The information of thethird network element may be transmitted using a data structure from oneof the following: a container, a container and multiple explicitinformation elements, multiple containers, or multiple containers andmultiple explicit information elements.

In some embodiments, the first core network and the second core networkare the same core network. In some embodiments, the first core networkand the second core network are different core networks.

In some embodiments, the second network element and the third networkelement operate using a first radio access technology (RAT). The firstRAT may be a fourth generation (4G) RAT technology. The first RAT may bea fifth generation (5G) RAT technology.

In some embodiments, the first network element and the fourth networkelement operating using a second RAT. In some implementations, the firstRAT and the second RAT correspond to different protocol standards. Insome implementations, the first RAT and the second RAT correspond to asame protocol standard.

In some embodiments, the information from the second network element isincluded in a data structure from one of the following: a container, acontainer and multiple explicit information elements, multiplecontainers, or multiple containers and multiple explicit informationelements. In some embodiments, the above described data structure mayalso include some or all configuration information of the first networkelement.

In another exemplary aspect, a wireless communications apparatuscomprising a processor is disclosed. The processor is configured toimplement a method described herein.

In yet another exemplary aspect, the various techniques described hereinmay be embodied as processor-executable code and stored on acomputer-readable program medium.

The details of one or more implementations are set forth in theaccompanying attachments, the drawings, and the description below. Otherfeatures will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a signaling flow for a change of thesecondary base stations in the LTE systems.

FIG. 2 shows an example of a signaling flow of a handover of a terminalfrom a first network element to a third network element.

FIG. 3 shows an exemplary change of master base stations that istriggered through a direct interface.

FIG. 4 shows an exemplary change of master base station that istriggered through an indirect interface.

FIG. 5 shows an exemplary change of master base stations withmeasurement information of transmissions.

FIG. 6 shows another exemplary change of master base stations withmeasurement information of transmissions.

FIG. 7 shows a schematic diagram of an exemplary configuration of corenetworks and network elements.

FIG. 8 is a flowchart representation of an exemplary method of wirelesscommunication.

FIG. 9 is another flowchart representation of an exemplary method ofwireless communication.

FIG. 10 is a block diagram of an example of a wireless communicationapparatus.

FIG. 11 shows an example of wireless communications network wheretechniques in accordance with one or more embodiments of the presenttechnology can be applied.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The following abbreviations are used in the present document.

MeNB Master eNB SeNB Secondary eNB MgNB Master gNB SgNB Secondary gNB MNMaster Node SN Secondary Node PCell Primary Cell PSCell PrimarySecondary Cell Scell Secondary Cell

Cellular mobile communication systems have evolved over the years. Afterseveral decades of development, the current fourth generation (4G, 4thGeneration) mobile communication systems have a wide variety ofapplications. To meet the increased demand for bandwidth, the fifthgeneration (5G, 5th Generation) mobile communication architecture isbeing developed to provide higher throughput, lower latency, and greateruser volume of diversified business services. For 4G systems, such asthe Long Term Evolution (LTE) systems, the base station is referred toas eNB (E-UTRAN NodeB), the core network is referred to as EPC (EvolvedPacket Core). In the 5G architecture, the base station is referred to asgNB (Global NodeB), and the core network is referred to as 5GC (5GGeneration Core).

In order to ensure that, in the future, operators can smoothly evolvefrom 4G mobile communication systems to 5G mobile communication systemsin network deployments, in the initial stage of 5G research, a 4G/5Gdual connectivity solution is proposed, which uses both 4G and 5G basestations (dual connectivity, also referred to as DC). In dualconnectivity communication, the core network types for the connectionsand the types of master and secondary base stations are different. Thepossible combinations can be divided into a variety of 4G/5G dual-linknetworking scenarios, such as:

1) a 4G master base station and a 5G secondary base station, connectedconcurrently to a 4G core network,

2) a 5G master base station and a 4G secondary base station, connectedconcurrently to a 5G core network, and

3) a 4G master base station and a 5G secondary base station, connectedconcurrently to a 5G core network.

Furthermore, in 5G mobile communication systems, in order to ensure that5G users may receive high bandwidth connectivity, 5G base stationswithin a 5G core network are used for dual connectivity (i.e., both themaster base station and the secondary base station are 5G basestations).

In the present document, the primary base station is collectivelyreferred to as MN, Master Node (MN), or Master Cell Group (MCG). Thesecondary base station is collectively referred to as Secondary node(SN), or Secondary Cell Group (SCG).

Due to the mobility of a user device or a terminal, in theabove-mentioned dual connectivity scenarios, the terminal may performthe site update once the terminal is moved out of the coverage of thecurrent master or secondary base stations. In the traditional technologyLTE systems, the following ways of changing the master or secondary basestations are supported:

1. In the case of dual connectivity, the master base station changes,but the secondary base station remains unchanged. This case may also bereferred to as inter-MeNB handover without SeNB change.

2. In the case of dual connectivity, the secondary base station changes,but the master base station remains unchanged. This case may also bereferred to as change of SeNB.

3. In the case of dual connectivity, the master base station changes,and the secondary base station gets removed. This case may also bereferred to as MeNB to eNB change.

4. In the case of single connectivity (e.g., without a secondary basestation), the master base station changes, and a secondary base stationis added. This case may also be referred to as eNB to MeNB change.

In the dual connectivity scenarios in the LTE systems, when thesecondary base station is triggered to change (e.g., change of SeNB),the process can only be initiated by the master base station. FIG. 1shows an example of a signaling flow for a change of a secondary basestation in the LTE systems.

At 102, the master base station 151 triggers a change of the secondarybase station.

At 104, the master base station 151 sends a request to a targetsecondary base station 153 for the change. The request may includeconfiguration information of the master base station 151 and the sourcesecondary base station 152. The request may also include service relatedinformation for the target secondary base station 153.

At 106, the target secondary base station 153 receives the request andestablishes corresponding configuration in the target secondary basestation 153 based on the received request. The target secondary basestation 153 then compares the configuration information between thesource secondary base station 152 and the target secondary base station153. The target secondary base station 153 generates supplementalconfiguration information, which represents the delta between theconfiguration information of the source secondary base station 152 andthe configuration information of the target secondary base station 153,based on the comparison.

At 108, the target secondary base station 153 transmits a response tothe master base station 151. The response may include the generatedsupplemental configuration information.

At 110, the master base station 151 then sends a release request to thesource secondary base station 152.

At 112, the master base station 151 transmits an air interfaceconfiguration message to the terminal with the supplementalconfiguration information of the target secondary base station 153 andother configuration information of the source master base station 151.

At 114, the terminal performs configuration based on the message fromthe master base station 151, and transmits another message to confirmthe configuration.

At 116, the master base station 151 transmits a response to the targetsecondary base station 153 to notify that the configuration hascompleted.

Unlike the 5G dual connectivity and the 4G/5G dual connectivity, in thedual connectivity of the LTE systems, the master base station alwaysstores the latest wireless configuration information of the secondarybase station because the air interface configuration can only beperformed by the master base station. In order to obtain thesupplemental configuration of the wireless parameters of the terminal,the request sent from the master base station to the new targetsecondary base station (i.e., SN addition request) can carry all thewireless configuration information of the current secondary base station(i.e., the source secondary base station) to assist the target secondarystation adjust its configuration, so as to avoid reset and/orre-establishment of the user plane, MAC, and other relevant informationand to avoid packet loss to ensure good user experiences.

One technical problem in the traditional LTE systems with dualconnectivity is that such a system does not support simultaneouschanging of the master base station and the secondary base station. Dueto this limitation, when the master base station changes, the secondarybase station remains unchanged. In order to have a different secondarybase station, a terminal needs to first delete the old secondary basestation, and then triggers an addition of a new secondary base stationindependently. Therefore, for 5G dual connectivity or 4G/5G dualconnectivity, a two-step process is needed when the master and secondarybase stations need to change at the same time: (1) to delete the oldsecondary base station, and (2) to add the new secondary base station.This two-step process may adversely affect user data throughput and userexperience during mobility.

Furthermore, the current LTE technology does not provide a solution fortransmitting configuration information of the old secondary base station(i.e., source) to the new secondary base station (i.e., target),especially for the 4G/5G dual connectivity scenarios. Since the wirelessbase stations belong to different mobile communication systems in the4G/5G dual connectivity scenarios, there are differences between the airinterface specifications. Moreover, in 4G/5G dual connectivity, themater base station and the secondary base station belong to differentradio access technology, which cannot comprehend each other's codelogic, and may have separate air interface configuration orreconfiguration mechanism, and the partial configuration orreconfiguration process triggered by the secondary base station isinvisible to the master base station. Therefore, the master base stationcannot obtain the complete configuration information from the secondarybase station. During simultaneous change of the master and secondarybase stations, the new secondary base station cannot obtain theconfiguration information of the old secondary base station. The newsecondary base station thus cannot support the supplementalconfiguration information for the terminal. A full configuration of theair interface may be required, which may result in user data packet lossand thereby affects user experiences.

The present document provides techniques that can be applied for a dualconnectivity in which the terminal is connected to the master basestation and the secondary base station at the same time. When a terminalswitches its master and secondary base stations, both base stations canbe switched at the same time (also referred to as Inter-Master Nodehandover with Secondary Node change). That is, the terminal switchesfrom a source dual-link master and secondary base stations to a targetdual-link master and secondary base stations.

In the description below, the source master base station is defined as afirst network element, the source secondary base station is defined as asecond network element, the target master base station is defined as athird network element, the target secondary base station is defined as afourth network element, and the core network is defined as the fifthnetwork element. FIG. 7 shows a schematic diagram of an exemplaryconfiguration of core networks and network elements.

The techniques provide a method and an apparatus for configuringinformation between the source and target dual-link master and secondarybase stations to solve the problem that the target secondary basestation cannot obtain the complete configuration information of thesource secondary base station.

FIG. 2 shows an example of a signaling flow of a handover of a terminalfrom a first network element to a third network element with a changefrom a second network element to a fourth network element. In FIG. 2,the terminal is connected to the first network element 251 and thesecond network element 252. The first network element 251 first obtainsrelevant information of the second network element 252. The firstnetwork element 251 may obtain the relevant information by sending amessage to the second network element 252 to request for suchinformation and receiving a response from the second network element 252that includes the relevant information. In some embodiments, the secondnetwork element 252 may send the information to the first networkelement when the information changes. The relevant information of thesecond network element 252 may be in a data structure one of thefollowing forms: one container, one container and explicit informationelements, multiple containers, or multiple containers and explicitinformation elements. A container can be a transparent container, suchas a Source To Target Transparent Container or a Target to SourceTransparent Container used in current LTE systems. Each container mayinclude multiple information elements for parameter configurations. Theuse of container(s) ensures that only the target node can decode theinformation included in the container. The use of explicit informationelement(s), on the other hand, allow both the target node and theintermediate relay node(s) to decode and/or modify the informationincluded therein. The data structure may also include configurationinformation, some or all, of the first network element.

The relevant information of the second network element 252 includes butis not limited to the configuration information of the primary cell andthe secondary cell(s) under the second network element 252 and relevantmeasurement information provided by the second network element 252. Insome embodiments, a secondary cell under the second network element 252is a secondary cell under the second base station in carrier aggregation(CA) scenarios. In some implementations, the number of the secondarycells is greater than or equal to 0.

In some embodiments, the configuration information of the primary cellunder the second network element 252 includes at least one of thefollowing: carrier configuration information, user plane configurationinformation, physical resource common configuration information,physical resource specific configuration information, MAC layerconfiguration, measurement configuration, and measurement results.

The configuration information of the secondary cell under the secondnetwork element 252 includes at least one of the following information:carrier configuration information, user plane configuration information,physical resource common configuration information, physical resourcespecific configuration information, MAC layer configuration information,measurement configuration, and measurement results.

At 202, the first network element 251 initiates the terminal to handover to the third network element 253. The first network element 251sends, at 204, a request to the third network element 253 and transmitsthe relevant information of the second network element 252 together withthe relevant information of the first network element 251 to the thirdnetwork element 253. The first network element 251 may transmit therelevant information directly to the third network element 253. In someembodiments, the first network element 251 transmits the relevantinformation to the fifth network element 255 first, and then theinformation is indirectly transmitted from the fifth network element 255to the third network element 253. The relevant information of the secondnetwork element 252 and the relevant information of the first networkelement 251 may be in a data structure in one of the following forms:one container, one container and explicit information elements, multiplecontainers, or multiple containers and explicit information elements.The data structure may also include at least some configurationinformation of the first network element.

The third network element 253 obtains the relevant information of thesecond network element 252 and the relevant information of the firstnetwork element 251 and determines, at 206, whether to change the secondnetwork element 252 to the fourth network element 254. If the thirdnetwork element 253 determines so, it transmits, at 208, the relevantinformation of the second network element 252 to the fourth networkelement 254. The relevant information of the second network element maybe in a data structure in one of the following forms: one container, onecontainer and explicit information elements, multiple containers, ormultiple containers and explicit information elements. The datastructure may also include at least some configuration information ofthe first network element.

In some embodiments, the third network element 253 may determine whetheror not to perform the change based on the obtained measurementinformation. The measurement information obtained by the third networkelement 253 may include: the measurement information provided by thefirst network element 251, and/or the measurement information providedby the second network element 252. The received measurement informationmay be in a data structure one of the following forms: one container,one container and explicit information elements, multiple containers, ormultiple containers and explicit information elements. The datastructure may also include at least some configuration of the firstnetwork element.

In some embodiments, the third network element 253 obtains themeasurement information provided by the first network element 251 bydirect transmission of the information from the first network element251 to the third network element 253. Alternatively, the information canbe transmitted to the fifth network element 255 from the first networkelement 251, and the information is indirectly transmitted to the thirdnetwork element 253 by the fifth network element 255.

In some embodiments, the third network element 253 obtains themeasurement information provided by the second network element 252 usingthe following steps: (1) the first network element 251 obtains therelevant information of the second network element 252, and (2) thefirst network element 251 transmits the information directly to thethird network element 253. Alternatively, the third network element 253may obtain the measurement information using the following steps: (1)the first network element 251 obtains the relevant information of thesecond network element 252, (2) the first network element 251 transmitsthe information to the fifth network element 255, and (3) the fifthnetwork element 255 indirectly transmits the information to the thirdnetwork element 253. In each information transmission, the measurementinformation are may be in a data structure one of the following forms:one container, one container and explicit information elements, multiplecontainers, or multiple containers and explicit information elements.The data structure may also include at least some configurationinformation of the first network element.

In some embodiments, the third network element 253 may pass the obtainedrelevant information of the second network element 252 and/ormeasurement information to the fourth network element 254 for the fourthnetwork element 254 to perform primary cell selection. The relevantinformation and measurement information may be in a data structure inone of the following forms: one container, one container and explicitinformation elements, multiple containers, or multiple containers andexplicit information elements. Furthermore, after receiving the relevantinformation of the second network element 252, the fourth networkelement 254 may generate supplemental configuration information based onthe received information, the radio resource configuration information,the measurement configuration information, etc. The fourth networkelement 254 can transmit, at 210, the supplemental configurationinformation to the third network element 253. The third network element253 may further transmit, at 212, the supplemental configurationinformation of the fourth network element 254 along with other types ofinformation that the third network element 253 has generated to thefirst network element 251. The data structure may also include at leastsome or all configuration information of the first network element.

In some embodiments, the third network element 253 may transmit directlyto the first network element 251. In some implementations, the thirdnetwork element 253 transmits the information to the fifth networkelement 255, and the information is indirectly transmitted to the firstnetwork element 251 by the fifth network element 255.

At 214, the first network element 251 sends a release request to thesecond network element 252.

At 216, the first network element 251 transmits an air interfaceconfiguration message to the terminal to forward the relevantconfiguration information to the terminal.

At 218, the terminal performs configuration based on the message fromthe first network element 251, and transmits another message to thethird network element 253 to establish the connection.

At 220, the third network element 253 sends a confirmation message tothe fourth network element 254 to confirm the new connection.

The above mentioned methods are further explained in the followingembodiments.

Exemplary Embodiment 1

FIG. 3 shows an exemplary change of master base stations that istriggered through a direct interface between a source master basestation and a target master base station.

Step 1: The source master base station obtains, at 302, theconfiguration information of the source secondary base station. Thesource master base station can obtain the information by sending amessage to the source secondary base station. Alternatively, the sourcesecondary base station may send the information to the source masterbase station when its information changes. The obtained information ofthe source secondary base station may be in a data structure in one ofthe following forms: one container, one container and explicitinformation elements, multiple containers, or multiple containers andexplicit information elements.

Step 2: The source master base station determines, at 304, to trigger achange of base stations. The source master base station transmits, at306, a change request to the target master base station. The changerequest may include the configuration information of the source masterbase station. The change request may also include the configurationinformation of the source secondary base station obtained previously.

In some embodiments, the message may be a handover request message. Theinformation of the source base station and the information of the sourcesecondary base station may be in a data structure one of the followingforms: one container, one container and explicit information elements,multiple containers, or multiple containers and explicit informationelements. The configuration information of the secondary base stationsincludes configuration information of the primary cell (PSCell) and thesecondary cell (SCell) under the secondary base station.

In some embodiments, the secondary cell of a secondary base station is asecondary cell under the Carrier Aggregation (CA) scenario on thesecondary base station. The number of the secondary cells is equal to orgreater than 0.

In some embodiments, the configuration information of the primary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

In some embodiments, the configuration information of the secondary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

Step 3: After the target master base station receives the configurationinformation, it determines, at 308, whether a change of the secondarybase station is necessary. If the target master base station determinesso, it sends, at 310, a request to a target secondary base station. Therequest may include the configuration information of target master node.The request may also include the service information and theconfiguration information of the source secondary base station.

In some embodiments, the request sent by the target master base stationis an SN addition request message. In some implementations, theconfiguration information of target master node and the configurationinformation of the source secondary base station may be in a datastructure in one of the following forms: one container, one containerand explicit information elements, multiple containers, or multiplecontainers and explicit information elements.

Step 4: After receiving the request from the target master base station,the target secondary base station performs, at 312, resource allocationsbased on the service information in the message. The target secondarybase station may compare the configuration information between thetarget secondary base station and the source secondary base station togenerate supplemental configuration information for the target secondarybase station.

Step 5: The target secondary base station transmits, at 314, thesupplemental configuration information to the target master base stationvia a response message, indicating that resource allocations aresuccessful for the target secondary base station.

In some embodiments, the response message is an SN addition requestacknowledge message. In some implementations, the supplementalconfiguration information may be in a data structure in one of thefollowing forms: one container, or one container and explicitinformation elements, or more than one container, or more than onecontainer and explicit information elements.

Step 6: After receiving the response message, the target master basestation transmits, at 316, the configuration information of the targetmaster base station and/or the supplemental configuration information ofthe target secondary base station to the source master base station viaa response message.

In some embodiments, the response message may be a handover requestacknowledge message. The configuration information of the target masterbase station and/or the supplemental configuration information of thetarget secondary base station may be in one of the following forms inthe response message: one container, one container and explicitinformation elements, multiple containers, or multiple containers andexplicit information elements.

Step 7: After receiving the response message, the source master basestation sends, at 318, a release request message to the source secondarybase station to inform the source secondary base station to releaseresources.

Step 8: The source master base station also transmits, at 320, an airinterface configuration message to the terminal to forward the relevantconfiguration information to the terminal.

Step 9: After the terminal completes the air interface configuration,the random access procedure of the target master station and the targetsecondary base station is started and the air interface configurationsuccess message is sent, at 322, to the target master base station.

Step 10: After receiving the response at the target master base stationat 324, the target master base station notifies the target secondarybase station of the new connection.

Step 11: The network performs user data back-propagation andcorresponding core-side upper-layer switching process.

Exemplary Embodiment 2

FIG. 4 shows an exemplary change of master base station that istriggered through an indirect interface. The example is applicable whenthere is no direct interface between the source master base station andthe target master base station, or when the core network type changes.

Step 1: The source master base station obtains, at 402, theconfiguration information of the source secondary base station. Thesource master base station can obtain the information by sending amessage to the source secondary base station. Alternatively, the sourcesecondary base station may send the information to the source masterbase station when its information changes. The obtained information ofthe source secondary base station may be in a data structure in one ofthe following forms: one container, or one container and explicitinformation elements, or more than one containers, or more than onecontainers and explicit information elements. The data structure mayalso include configuration information, some or all, of the sourcemaster base station.

Step 2: The source master base station determines, at 404, to trigger achange of base stations. The source master base station transmits, at406, a change request to the core network. The change request mayinclude the configuration information of the source master base station.The change request may also include the configuration information of thesource target base station obtained in Step 1.

In some embodiments, the message may be a handover required message. Theinformation of the source base station and the information of the sourcesecondary base station may be in a data structure in one of thefollowing forms: one container, one container and explicit informationelements, multiple containers, or multiple containers and explicitinformation elements. The configuration information of the secondarybase stations includes configuration information of the primary cell(PSCell) and the secondary cell (SCell) under the secondary basestations.

In some embodiments, the secondary cell of the secondary base station isa secondary cell under the Carrier Aggregation (CA) scenario on thesecondary base station. The number of the secondary cells is equal to orgreater than 0.

In some embodiments, the configuration information of the primary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

In some embodiments, the configuration information of the secondary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

Step 3: After the core network receives the above-mentioned message andconfiguration information, the core network transmits, at 408, a messageto the target master base station based on an identification of thetarget master base station included in the message. The message may alsoinclude service information, configuration information of the sourcemaster base station, and configuration information of the sourcesecondary base station.

In some embodiments, the message may be a handover request message. Insome implementations, the information of the source base station and theinformation of the source secondary base station may be in one of thefollowing forms: one container, one container and explicit informationelements, multiple containers, or multiple containers and explicitinformation elements.

Step 4: After receiving the message and the configuration informationfrom the core network, the target master base station determines, at410, whether it is necessary to change the secondary base station. Ifthe target master base station determines so, it sends, at 412, arequest to a target secondary base station. The request may include theconfiguration information of target master node. The request may alsoinclude the service information and the configuration information of thesource secondary base station.

In some embodiments, the request sent by the target master base stationis an SN addition request message. In some implementations, theconfiguration information of target master node and the configurationinformation of the source secondary base station may be in a datastructure in one of the following forms: one container, one containerand explicit information elements, multiple containers, or multiplecontainers and explicit information elements. The data structure mayalso include some or all configuration information of the source masterbase station.

Step 5: After receiving the request from the target master base station,the target secondary base station performs, at 414, resource allocationsbased on the service information in the message. The target secondarybase station may compare the configuration information between thetarget secondary base station and the source secondary base station togenerate supplemental configuration information for the target secondarybase station.

Step 6: The target secondary base station transmits, at 416, thesupplemental configuration information to the target master base stationthrough a response message, indicating that resource allocations aresuccessful for the target secondary base station.

In some embodiments, the response message is an SN addition requestacknowledge message. In some implementations, the supplementalconfiguration information may be in one of the following forms: onecontainer, one container and explicit information elements, multiplecontainers, or multiple containers and explicit information elements.

Step 7: After receiving the response message, the target master basestation transmits, at 418, the configuration information of the targetbase station and/or the supplemental configuration information of thetarget secondary base station to the core network via another responsemessage.

In some embodiments, the response message may be a handover requestacknowledge message. The configuration information of the target masterbase station and/or the supplemental configuration information of thetarget secondary base station may be in a data structure one of thefollowing forms in the response message: one container, one containerand explicit information elements, multiple containers, or multiplecontainers and explicit information elements.

Step 8: After receiving the above message and configuration information,the core network transmits, at 420, a response message to the sourcemaster base station. The response message may include the configurationinformation of the target master base station and/or the supplementalconfiguration information of the target secondary base station.

In some embodiments, the response message is a handover command message.The configuration information of the target base station and/or thesupplemental configuration information of the target secondary basestation may be in one of the following forms in the response message:one container, one container and explicit information elements, multiplecontainers, or multiple containers and explicit information elements.

Step 9: After receiving the response message, the source master basestation sends, at 422, a release request message to the source secondarybase station to inform the source secondary base station to releaseresources.

Step 10: The source master base station also transmits, at 424, an airinterface configuration message to the terminal to forward the relevantconfiguration information to the terminal.

Step 11: After the terminal completes the air interface configuration,the random access procedure of the target master base station and thetarget secondary base station is started and the air interfaceconfiguration success message is sent, at 426, to the target master basestation.

Step 12: After receiving the response at the target master base stationat 428, the target master base station notifies the target secondarybase station of the new connection.

Step 13: The network performs user data back-propagation andcorresponding core-side upper-layer switching process.

Exemplary Embodiment 3

FIG. 5 shows an exemplary change of master base stations withmeasurement information of transmissions.

Step 1: The source master base station obtains, at 502, theconfiguration information of the source secondary base station. Thesource master base station can obtain the information by sending amessage to the source secondary base station. Alternatively, the sourcesecondary base station may send the information to the source masterbase station when its information changes. The obtained information ofthe source secondary base station may be in one of the following forms:one container, one container and explicit information elements, multiplecontainers, or multiple containers and explicit information elements.

Step 2: The source master base station determines, at 504, to trigger achange of base stations. The source master base station transmits, at506, a change request to the target master base station. The changerequest may include the configuration information of the source masterbase station. The change request may also include the configurationinformation of the source secondary base station obtained previously.The change request may further include measurement results sent from theterminal to the source master base station.

In some embodiments, the message may be a handover request message. Theinformation of the source base station and the information of the sourcesecondary base station, and the measurement information/results may bein one of the following forms: one container, one container and explicitinformation elements, multiple containers, or multiple containers andexplicit information elements. The configuration information of thesecondary base stations includes configuration information of theprimary cell (PSCell) and the secondary cell (SCell) under the secondarybase stations.

In some embodiments, the secondary cell of a secondary base station is asecondary cell under the Carrier Aggregation (CA) scenario on thesecondary base station. The number of the secondary cells is equal to orgreater than 0.

In some embodiments, the configuration information of the primary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

In some embodiments, the configuration information of the secondary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

Step 3: After receiving the message and the configuration information,the target master base station determines, at 508, whether it isnecessary to change the secondary base station based on the measurementinformation and/or measurement results included in the message. If thetarget master base station determines so, it transmits, at 510, arequest to a target secondary base station. The request may include theconfiguration information of target master node, The request may alsoinclude service information and the configuration information of thesource secondary base station. The request may also include measurementinformation and/or measurement results.

In some embodiments, the request sent by the target master base stationis an SN addition request message. In some implementations, theconfiguration information of target master node, the configurationinformation of the source secondary base station and the measurementinformation and/or measurement results may be in one of the followingforms: one container, one container and explicit information elements,multiple containers, or multiple containers and explicit informationelements.

Step 4: After receiving the request from the target master base station,the target secondary base station selects, at 512, the target primarycell based on the measurement information and/or measurement results,and performs resource allocations based on the service informationincluded in the message. The target secondary base station may comparethe configuration information between the target secondary base stationand the source secondary base station to generate supplementalconfiguration information for the target secondary base station.

Step 5: The target secondary base station transmits, at 514, thesupplemental configuration information to the target master base stationthrough a response message, indicating that resource allocations aresuccessful for the target secondary base station.

In some embodiments, the response message is an SN addition requestacknowledge message. In some implementations, the configurationinformation may be in one of the following forms: one container, onecontainer and explicit information elements, multiple containers, ormultiple containers and explicit information elements.

Step 6: After receiving the response message, the target master basestation transmits, at 316, the configuration information of the targetmaster base station and/or the supplemental configuration information ofthe target secondary base station to the source master base station viaa response message.

In some embodiments, the response message may be a handover requestacknowledge message. The configuration information of the target masterbase station and/or the supplemental configuration information of thetarget secondary base station may be in one of the following forms inthe response message: one container, one container and explicitinformation elements, multiple containers, or multiple containers andexplicit information elements.

Step 7: After receiving the response message, the source master basestation sends, at 518, a release request message to the source secondarybase station to inform the source secondary base station to releaseresources.

Step 8: The source master base station also transmits, at 520, an airinterface configuration message to the terminal to forward the relevantconfiguration information to the terminal.

Step 9: After the terminal completes the air interface configuration,the random access procedure of the target master station and the targetsecondary base station is started and the air interface configurationsuccess message is sent, at 522, to the target master base station.

Step 10: After receiving the response at the target master base stationat 524, the target master base station notifies the target secondarybase station of the new connection.

Step 11: The network performs user data back-propagation andcorresponding core-side upper-layer switching process.

Exemplary Embodiment 4

FIG. 6 shows another exemplary change of master base stations withmeasurement information of transmissions.

Step 1: The source master base station obtains, at 602, theconfiguration information and measurement information/results of thesource secondary base station. The source master base station can obtainthe information by sending a message to the source secondary basestation. Alternatively, the source secondary base station may send theinformation to the source master base station when its informationchanges. The obtained configuration information and measurementinformation/results of the source secondary base station may be in oneof the following forms: one container, one container and explicitinformation elements, multiple containers, or multiple containers andexplicit information elements.

Step 2: The source master base station determines, at 604, to trigger achange of base stations. The source master base station transmits, at606, a change request to the target master base station. The changerequest may include the configuration information of the source masterbase station. The change request may also include the configurationinformation of the source secondary base station obtained previously.The change request may further include measurement information/resultsof the source secondary base station obtained previously. The changerequest may further include measurement results sent from the terminalto the source master base station.

In some embodiments, the message may be a handover request message. Theinformation of the source base station and the information of the sourcesecondary base station, and the measurement information/results may bein one of the following forms: one container, or one container andexplicit information elements, multiple containers, or multiplecontainers and explicit information elements. The configurationinformation of the secondary base stations includes configurationinformation of the primary cell (PSCell) and the secondary cell (SCell)under the secondary base stations.

In some embodiments, the secondary cell of a secondary base station is asecondary cell under the Carrier Aggregation (CA) scenario on thesecondary base station. The number of the secondary cells is equal to orgreater than 0.

In some embodiments, the configuration information of the primary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

In some embodiments, the configuration information of the secondary cellincludes one or more of the following: carrier configurationinformation, user plane configuration information, physical resourcecommon configuration information, physical resource specificconfiguration information, MAC layer configuration information,measurement configuration information, and measurement results.

Step 3: After receiving the message and the configuration information,the target master base station determines, at 608, whether it isnecessary to change the secondary base station based on the measurementinformation/results of the source secondary base station included in themessage. If the target master base station determines so, it transmits,at 610, a request to a target secondary base station. The request mayinclude the configuration information of target master node. The requestmay also include service information and the configuration informationof the source secondary base station. The request may also includemeasurement information and/or measurement results.

In some embodiments, the request sent by the target master base stationis an SN addition request message. In some implementations, theconfiguration information of target master node, the configurationinformation of the source secondary base station and the measurementinformation and/or measurement results may be in one of the followingforms: one container, one container and explicit information elements,multiple containers, or multiple containers and explicit informationelements.

Step 4: After receiving the request from the target master base station,the target secondary base station selects, at 612, the target primarycell based on the measurement information and/or measurement results,and performs resource allocations based on the service informationincluded in the message. The target secondary base station may comparethe configuration information between the target secondary base stationand the source secondary base station to generate supplementalconfiguration information for the target secondary base station.

Step 5: The target secondary base station transmits, at 614, thesupplemental configuration information to the target master base stationthrough a response message, indicating that resource allocations aresuccessful for the target secondary base station.

In some embodiments, the response message is an SN addition requestacknowledge message. In some implementations, the configurationinformation may be in one of the following forms: one container, onecontainer and explicit information elements, multiple containers, ormultiple containers and explicit information elements.

Step 6: After receiving the response message, the target master basestation transmits, at 616, the configuration information of the targetmaster base station and/or the supplemental configuration information ofthe target secondary base station to the source master base station viaa response message.

In some embodiments, the response message may be a handover requestacknowledge message. The configuration information of the target masterbase station and/or the supplemental configuration information of thetarget secondary base station may be in one of the following forms inthe response message: one container, or one container and explicitinformation elements, multiple containers, or multiple containers andexplicit information elements.

Step 7: After receiving the response message, the source master basestation sends, at 618, a release request message to the source secondarybase station to inform the source secondary base station to releaseresources.

Step 8: The source master base station also transmits, at 620, an airinterface configuration message to the terminal to forward the relevantconfiguration information to the terminal.

Step 9: After the terminal completes the air interface configuration,the random access procedure of the target master station and the targetsecondary base station is started and the air interface configurationsuccess message is sent, at 622, to the target master base station.

Step 10: After receiving the response at the target master base stationat 624, the target master base station notifies the target secondarybase station of the new connection.

Step 11: The network performs user data back-propagation andcorresponding core-side upper-layer switching process.

In the various message exchange scenarios described in the presentdocument, in some embodiments, when a source master base station sendsconfiguration information to a target master base station, it may sendinformation of the source master base station and information of thesource secondary base station. In some embodiments, when the targetmaster base station sends configuration information to the targetsecondary base station, that information may also include information ofthe target master base station, and information of the source secondarybase station.

FIG. 8 is a flowchart representation of an exemplary method of wirelesscommunication 800. The method 800 includes, at 802, providingconnectivity between a first core network and a user device. The method800 also includes, at 804, communicating configuration information of asecond network element.

In some embodiments, the method includes operating a first networkelement in a wireless communication network to provide connectivitybetween a first core network and a user device, wherein the wirelesscommunication network includes a second network element that isconfigured to provide a secondary connectivity between the first corenetwork and the user device; and communicating, by the first networkelement, in a handover to a third network element configured to provideconnectivity with a second core network, configuration information ofthe second network element to the third network element.

FIG. 9 is another flowchart representation of an exemplary method ofwireless communication 900. The method 900 includes, at 902, providingconnectivity to a core network; at 904, receiving information of anetwork element providing secondary connectivity; and at 906,selectively deciding a network element that provides secondaryconnectivity.

In some embodiments, the method includes operating a first networkelement to provide connectivity to a first core network; receiving, whena user device is handed over from a second network element, informationfrom the second network element providing connectivity to a second corenetwork, wherein the information identifies properties of a thirdnetwork element providing a secondary connectivity to the second corenetwork; and selectively deciding, based on the information, a secondaryconnectivity network element between the third network element and afourth network element for the first network element, wherein the fourthnetwork element is configured to provide connectivity to the first corenetwork.

FIG. 10 is a block diagram of an example of a wireless communicationapparatus. The apparatus 1000, such as a base station or a wirelessdevice (or a terminal), can include processor electronics 1010 such as amicroprocessor that implements one or more of the wireless techniquespresented in this document. The apparatus 1000 can include transceiverelectronics 1015 to send and/or receive wireless signals over one ormore communication interfaces such as antenna 1020. The apparatus 1000can include other communication interfaces for transmitting andreceiving data. The apparatus 1000 can include one or more memories 1005configured to store information such as data and/or instructions. Insome implementations, the processor electronics 1010 can include atleast a portion of the transceiver electronics 1015. In someembodiments, at least some of the disclosed techniques, modules orfunctions are implemented using the apparatus 1000.

FIG. 11 shows an example of wireless communications network wheretechniques in accordance with one or more embodiments of the presenttechnology can be applied. A wireless communication system 1300 caninclude one or more base stations (BSs) 1302, one or more wirelessdevices 1306, and a core network 1312. The base station 1302 can providewireless service to wireless devices 1306 in one or more wirelesssectors. In some implementations, a base station 1302 includesdirectional antennas to produce two or more directional beams to providewireless coverage in different sectors.

The core network 1312 provides connectivity with other wirelesscommunication systems and wired communication systems. The core networkmay include one or more service subscription databases to storeinformation related to the subscribed wireless devices 1306. A firstbase station can provide wireless service based on a first radio accesstechnology, whereas a second base station can provide wireless servicebased on a second radio access technology. The base stations may beco-located or may be separately installed in the field according to thedeployment scenario.

In some implementations, a wireless communication system can includemultiple networks using different wireless technologies. A dual-mode ormulti-mode wireless device includes two or more wireless technologiesthat could be used to connect to different wireless networks.

It is thus evident that the techniques disclosed in the present documentprovide a method and an apparatus for configuring transmission forsupporting simultaneous change of the master and secondary basestations. The target secondary base station is also capable of obtaininginformation regarding the source secondary base station without a fullre-configuration of the air interface, thereby avoiding user data packetloss and maintaining good user experiences.

The disclosed and other embodiments, modules and the functionaloperations described in this document can be implemented in digitalelectronic circuitry, or in computer software, firmware, or hardware,including the structures disclosed in this document and their structuralequivalents, or in combinations of one or more of them. The disclosedand other embodiments can be implemented as one or more computer programproducts, i.e., one or more modules of computer program instructionsencoded on a computer readable medium for execution by, or to controlthe operation of, data processing apparatus. The computer readablemedium can be a machine-readable storage device, a machine-readablestorage substrate, a memory device, a composition of matter effecting amachine-readable propagated signal, or a combination of one or morethem. The term “data processing apparatus” encompasses all apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, or multiple processors or computers.The apparatus can include, in addition to hardware, code that creates anexecution environment for the computer program in question, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, or a combination of one or moreof them. A propagated signal is an artificially generated signal, e.g.,a machine-generated electrical, optical, or electromagnetic signal, thatis generated to encode information for transmission to suitable receiverapparatus.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this document can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read only memory ora random access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto optical disks, or optical disks. However, a computerneed not have such devices. Computer readable media suitable for storingcomputer program instructions and data include all forms of non-volatilememory, media and memory devices, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks;magneto optical disks; and CD ROM and DVD-ROM disks. The processor andthe memory can be supplemented by, or incorporated in, special purposelogic circuitry.

While this document contains many specifics, these should not beconstrued as limitations on the scope of an invention that is claimed orof what may be claimed, but rather as descriptions of features specificto particular embodiments. Certain features that are described in thisdocument in the context of separate embodiments can also be implementedin combination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesub-combination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asub-combination or a variation of a sub-combination. Similarly, whileoperations are depicted in the drawings in a particular order, thisshould not be understood as requiring that such operations be performedin the particular order shown or in sequential order, or that allillustrated operations be performed, to achieve desirable results.

Only a few examples and implementations are disclosed. Variations,modifications, and enhancements to the described examples andimplementations and other implementations can be made based on what isdisclosed.

What is claimed is:
 1. A method for wireless communication, comprising:transmitting, by a target master base station to a target secondary basestation, a request indicating a change from a source secondary basestation to the target secondary base station for a terminal device,wherein the request comprises configuration information of the sourcesecondary base station; and receiving, by the target master basestation, a response from the target secondary base station indicatingthat a resource allocation for the change is successful, wherein theresponse further comprises supplemental configuration informationindicating a difference between the configuration information of thesource secondary base station and a configuration information of thetarget secondary base station.
 2. The method of claim 1, wherein therequest comprises a secondary node addition request.
 3. The method ofclaim 1, wherein the response comprises a secondary addition requestacknowledgement message.
 4. The method of claim 1, wherein thesupplemental configuration information is included in a data structurehaving one or more containers.
 5. The method of claim 1, furthercomprising: transmitting, by the target master base station, thesupplemental configuration information to a source master base stationto enable a reconfiguration of the terminal device.
 6. A method forwireless communication, comprising: receiving, by a target secondarybase station from a target master base station, a request indicating achange of from a source secondary base station to the target secondarybase station for a terminal device, wherein the request comprisesconfiguration information of the source secondary base station;performing, by the target secondary base station, a resource allocationfor the change in response to the request; and transmitting, by thetarget secondary base station, a response to the target master basestation indicating that the resource allocation for the change issuccessful, wherein the response further comprises supplementalconfiguration information indicating a difference between theconfiguration information of the source secondary base station and aconfiguration information of the target secondary base station to enablea reconfiguration of the terminal device.
 7. The method of claim 6,wherein the request comprises a secondary node addition request.
 8. Themethod of claim 6, wherein the response comprises a secondary additionrequest acknowledgement message.
 9. The method of claim 6, wherein thesupplemental configuration information is included in a data structurehaving one or more containers.
 10. The method of claim 6, furthercomprising: generating, by the target secondary base station, thesupplemental configuration information by comparing the configurationinformation of the source secondary base station and configurationinformation of the target secondary base station.
 11. A device forwireless communication implemented as a target master base station, thedevice comprising a processor that is configured to: transmit a requestto a target secondary base station indicating a change from a sourcesecondary base station to the target secondary base station for aterminal device, wherein the request comprises configuration informationof the source secondary base station; and receive a response from thetarget secondary base station indicating that a resource allocation forthe change is successful, wherein the response further comprisessupplemental configuration information indicating a difference betweenthe configuration information of the source secondary base station and aconfiguration information of the target secondary base station.
 12. Thedevice of claim 11, wherein the request comprises a secondary nodeaddition request.
 13. The device of claim 11, wherein the responsecomprises a secondary addition request acknowledgement message.
 14. Thedevice of claim 11, wherein the supplemental configuration informationis included in a data structure having one or more containers.
 15. Thedevice of claim 11, wherein the processor is configured to: transmit thesupplemental configuration information to a source master base stationto enable a reconfiguration of the terminal device.
 16. A device forwireless communication implemented as a target secondary base station,the device comprising a processor that is configured to: receiving arequest from a target master base station indicating a change of from asource secondary base station to the target secondary base station for aterminal device, wherein the request comprises configuration informationof the source secondary base station; perform a resource allocation forthe change in response to the request; and transmit a response to thetarget master base station indicating that the resource allocation forthe change is successful, wherein the response further comprisessupplemental configuration information indicating a difference betweenthe configuration information of the source secondary base station and aconfiguration information of the target secondary base station to enablea reconfiguration of the terminal device.
 17. The device of claim 16,wherein the request comprises a secondary node addition request.
 18. Thedevice of claim 16, wherein the response comprises a secondary additionrequest acknowledgement message.
 19. The device of claim 16, wherein thesupplemental configuration information is included in a data structurehaving one or more containers.
 20. The device of claim 16, wherein theprocessor is configured to: generate the supplemental configurationinformation by comparing the configuration information of the sourcesecondary base station and configuration information of the targetsecondary base station.